Recently, on-vehicle audio-video (AV) devices become more sophisticated and require support for many multimedia formats and a variety of input sources, including nonvolatile memory devices such as hard disk drives (HDDs), SD card devices, and universal serial bus (USB) memory devices, optical disc devices for compact disks (CDs), digital versatile disks (DVDs), Blu-ray disks (BDs) (registered trademark), or other disks, portable AV players such as mobile audio players and mobile AV players, wireless networks such as wireless fidelity (WiFi), and so on. There is also an increasing demand to enjoy the same or different content on a front passenger seat, a left rear seat, and a right rear seat.
Further, some content items contain information for digital rights management (DRM). Patent Document 1 describes a method for controlling the use of digital rights of the ‘Play N times’ type of digital audio content items or digital video content items.